A252729 Start with 1, add 1, subtract 2, multiply by 3, add 4, subtract 5, multiply by 6, add 7, etc.

1, 2, 0, 0, 4, -1, -6, 1, -7, -63, -53, -64, -768, -755, -769, -11535, -11519, -11536, -207648, -207629, -207649, -4360629, -4360607, -4360630, -104655120, -104655095, -104655121, -2825688267, -2825688239, -2825688268, -84770648040, -84770648009

Offset: 1

Author

Edwin McCravy, Dec 20 2014

Keywords

• sign
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Programs

Maple

A252729 := proc(n)
    option remember;
    if n =1 then
        1;
    elif modp(n,3) = 2 then
        procname(n-1)+n-1;
    elif modp(n,3) = 0 then
        procname(n-1)-(n-1);
    elif modp(n,3) = 1 then
        procname(n-1)*(n-1);
    fi ;
end proc:
seq(A252729(n),n=1..32) ; # R. J. Mathar, Mar 20 2015

Mathematica

nxt[{n_,a_}]:={n+1,Which[Mod[n+1,3]==1,a+n+1,Mod[n+1,3]==2,a-(n+1),True, a*(n+1)]}; Transpose[NestList[nxt,{0,1},35]][[2]] (* Harvey P. Dale, Mar 29 2015 *)